Greenland and Antarctic ice sheets lost over 11,000 billion tonnes of ice between 1979 and 2023

Between 1979 and 2023, the Greenland and Antarctic ice sheets together lost 11,309 billion tonnes of ice, contributing 3.14 centimeters to global sea-level rise. These findings are reported in a new study published in Scientific Data by the international IMBIE consortium (Ice Sheet Mass Balance Intercomparison Exercise), a collaboration of polar researchers from institutions around the world. The research combined data from 27 satellite missions and 42 independent measurements, producing the longest and most comprehensive satellite record ever compiled of changes in the two ice sheets. Among the co-authors are researchers Ernst Schrama from the Faculty of Aerospace Engineering and Pavel Ditmar and Bert Wouters from the Faculty of Civil Engineering and Geosciences at TU Delft.

The study found that the dominant driver of ice loss is not surface melt but the accelerated movement of outlet glaciers toward the sea. In total, 84 percent of the recorded ice loss was attributed to this accelerated ice outflow, while the remaining 16 percent resulted from changes in surface mass balance, including melt. Lead researcher Inès Otosaka of Northumbria University stated that by looking back to the 1970s, scientists can observe for the first time how the ice sheets have evolved over half a century, and that more than four-fifths of the lost ice was discharged directly into the ocean by faster-flowing glaciers, reflecting the long-term influence of a warming ocean on ice sheet dynamics.

The analysis documents a sharp acceleration in ice loss beginning in the 1990s. In the 1980s, Greenland lost an average of approximately 60 billion tonnes of ice per year. By the 2010s, that figure had risen to an average of 264 billion tonnes per year. Antarctica followed a similar trajectory, with annual losses increasing from around 48 billion tonnes in the 1980s to approximately 202 billion tonnes in the 2010s. In Antarctica, unlike Greenland, the net ice loss was almost entirely driven by the acceleration of outlet glaciers.

Of the combined 3.14 centimeters contributed to global sea-level rise, 1.81 centimeters originated from Greenland and 1.33 centimeters from Antarctica. Together, the two ice sheets are currently responsible for approximately one quarter of total global sea-level rise. Andrew Shepherd, founder of IMBIE, noted that an additional rise of just over three centimeters puts a further six to nine million people at risk of flooding and coastal erosion.

Between 2020 and 2023, total ice loss temporarily slowed. In East Antarctica, exceptionally heavy snowfall produced a net gain in ice mass, and Greenland experienced several relatively cool summers that reduced surface ice melt. The researchers clarified, however, that these developments do not represent a reversal of the long-term trend. The ice sheets continue to lose mass overall, and year-to-year variations in snowfall, temperature, and glacier flow can temporarily obscure the underlying trajectory.

The study draws on data from multiple satellite platforms, including ESA's CryoSat mission, the Copernicus Sentinel satellites, the GRACE and GRACE Follow-On gravimetry satellites, and Landsat missions. The dataset integrates 42 independent estimates of ice sheet mass balance derived from measurements of ice height, gravity, and ice flow. The Greenland record extends from 1972 to 2023, while the Antarctic record covers 1979 to 2023. According to ESA, long-term datasets of this kind form an essential foundation for understanding the role of ice sheets in a changing climate and for evaluating risks to the hundreds of millions of people living in low-lying coastal regions.